This invention relates to bows for use on resonating wood instruments such as violins, violas, cellos and the like and, more particularly, to a frog which can be readily adjusted by the player to provide optimum tension of the hair under any conditions.
Though most understand that a violin is a finely crafted and expensive instrument, the quality and adjustment of the bow also contributes to the quality of the sound generated by moving the hair of the bow across the strings of the violin. Bows can be formed of a bent, flexible, piece of metal or wood. Fine bows are formed of a bent wood having a length of hair attached between the head of the bow and a rear fixture known as a frog.
The length of hair is fixed and is set by a repairman at his shop. The hair is sensitive to tension, temperature and humidity. To avoid unnecessary stretching of the hair, the frog is removed from the base of the bow between performances to relieve tension on the hair. In the modern era, concerts are performed under widely varying environments. In the same locale, a concert could be performed indoors in a heated or air conditioned hall or outside in an open bowl under hot and dry conditions during the day or cold, humid conditions at night. The conditions further change from season to season, week to week and city to city.
The length of the hair on the bow will change as the hair experience different humidities and temperatures. The length will also change with use due to tension forces during playing. The hair can even lengthen excessively during a concert forcing a change of bows at intermission. Since the hair is set to an exact length at the shop of the repairman, a concert violinist is required to own a plurality of bows and has to equip them with different lengths of hair for different conditions. If the hair has been shortened for use under high temperature and humidity conditions, it will be too short to use when the temperature is lower requiring a very expensive replacement of the hair. Furthermore, the repairman and the musician are constantly guessing at the exact length to cut the hair. For example, a Los Angeles repairman preparing a bow to be used in Seattle has a very difficult problem of predicting the weather and estimating the length to cut the hair. This is a common situation since many performers trust only a single dealer or repairman who may be thousands of miles away. Unfortunately, the bow is rarely adjusted exactly and the musician has to perform under non-ideal conditions.